Abstract: The purpose of the proposed project is to study periodontal conditions in those residents of Tecumseh, Michigan, who participated in an oral epidemiological study conducted by Jamison and Ramfjord in 1959-1960. The background to this original periodontal study is that Tecumseh was selected in 1956 as the site of ongoing longitudinal epidemiological studies of chronic circulatory and respiratory disease. These medical studies have been operated continuously since 1956 by the Department of Epidemiology, School of Public Health, The University of Michigan. The original plan of Drs. Jamison and Ramfjord was to include periodontal disease as one of the chronic conditions to be followed in this major epidemiological study, but for various reasons no follow-up examinations were ever carried out. This proposed project is an unusual opportunity to study the natural history of periodontal conditions over a period of 27 years. Conditions to be measured will be level of periodontal attach Z01MH02395, gingivitis, and oral hygiene status. Participants will be all of those available from the original study; based upon data from the Department of Epidemiology, it is estimated that between 150 to 200 adults, aged 33 to 86, out of the 526 participants originally examined by Jamison in 1959-60 could be reexamined in 1987. The same criteria for measuring periodontal conditions used by Jamison in 1960 will be applied. Jamison's data provided detailed information about the loss of periodontal attachment by tooth site for all teeth present in the mouth (except third molars). This current opportunity to assess conditions after 27 years, made feasible by the careful records kept by the Department of Epidemiology, is an opportunity to make good that deficiency and to provide unique longitudinal data will be an important addition to our knowledge of periodontal disease.